Sn-doped In2O3 (ITO) thin films were fabricated on float glass substrates from a nanoparticle suspension using a new and
inexpensive aerosol-assisted chemical transport (AACT) process. The influence of the solvent type, loading level and film
deposition time on the structural, electrical and optical properties of the deposited thin films was investigated. In addition,
the effect of post-deposition heat-treatment of ITO films on the film resistivity and transparency was investigated using
microwave radiation and compared with more conventional radiant heat-treated films. The SEM images of the films
prepared using a 30 min deposition time with 0.20% (wt/vol%) methanolic ITO suspension provided better surface
coverage compared to the other deposition times investigated. The optimised ITO films were heat-treated after deposition
by either conventional radiant or microwave assisted heating methods in order to improve the inter-particle connections
and film adherence. The films heat-treated after deposition by microwave annealing exhibited an average transmittance of
>85% in the visible region with a resistivity of 12 Ω cm and a carrier concentration of -3.7 x 1016
cm
3
, which was superior
to films that were heat-treated using more conventional thermal processing (despite the shorter processing time for the
microwave process). The resistivity of ITO films was further decreased to 6.0 x 10-2 Ω cm with increased carrier
concentration of -8.0 x 1018
cm
3 when ethyl cellulose was added to the ITO suspension prior to the AACT deposition. The
enhanced conductivity of this film is due to the improved particle-particle and particle-substrate connections as observed
by SEM imaging.

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Sponsor:

This research was funded by the UK Engineering and Physical
Sciences Research Council (EPSRC) under grant number
EP/L017709/1. The authors also gratefully acknowledge the
support of the industrial collaborators, especially Malvern
Instruments Ltd., Sun Chemical Ltd. and NSG, Pilkington. The
assistance received from all members of the Energy Research
Laboratory in the Department of Chemistry, Loughborough
University is also acknowledged. The authors acknowledge use
of facilities with the Loughborough Materials Characterisation
centre (LMCC) and CREST Loughborough University. We would
like to thank Dr. Keith Yendall, Dr. Jagdeep Sagu and Dr.
Patrick Isherwood for their assistance given in getting titled
SEM images and Hall Effect measurements.